Light emitting device

ABSTRACT

A light emitting device includes: a ceramic substrate; a plurality of LED chips; a printed resistor(s) connected in parallel with the plurality of LED chips; a dam resin made of a resin having a low optical transmittance; a fluorescent-material-containing resin layer; and an anode-side electrode and a cathode-side electrode, (a) which are provided on a primary surface of the ceramic substrate so as to face each other along a first direction on the primary surface and (b) which are disposed below at least one of the dam resin and the fluorescent-material-containing resin layer. With the configuration in which a plurality of LEDs, which are connected in a series-parallel connection, are provided on a substrate, it is possible to provide a light emitting device which can achieve restraining of luminance unevenness and an improvement in luminous efficiency.

This is a continuation of U.S. patent application Ser. No. 13/011,124filed Jan. 21, 2011, which is a nonprovisional application which claimspriority under 35 U.S.C. §119(a) on Patent Application No. 2010-012486filed in Japan on Jan. 22, 2010, the entire contents of which are herebyincorporated by reference.

TECHNICAL FIELD

The present invention relates to a light emitting device including aplurality of light emitting elements provided in a series-parallelconnection, and a protective element(s), which is electrically connectedto the plurality of light emitting elements. Particularly, the presentinvention relates to a technique to restrain luminance unevenness and toimprove luminous efficiency.

BACKGROUND ART

As an improvement in luminous efficiency becomes more important inrecent years, LEDs (Light Emitting Diode) are being widely used inbacklights provided in a display device and lighting apparatuses as alight source that saves more energy than electric bulbs or fluorescentlamps. For these purposes, energy efficiency is very important.

However, LEDs, especially, gallium nitride LEDs are easily broken due toelectrostatic discharges. That is, the LEDs withstand only a smallreverse voltage. In order to prevent such a problem, there has beendisclosed a technique in which Zener diodes are connected to LEDs in aninverse-parallel connection (see Patent Literature 1, for example).

In such a configuration that employs the Zener diodes, when an excessivevoltage is applied in a forward direction, an excessive current isbypassed due to Zener breakdown. In the meantime, when an excessivevoltage is applied in a reverse direction, the Zener diodes serve asnormal forward diodes to bypass an excessive current. In this way, theLEDs are protected from the excessive voltage in either direction.Further, a forward voltage to be applied to the LEDs is smaller than aZener breakdown voltage of the Zener diodes. Even if the forward voltageis applied to the LEDs, no current flows into the Zener diodes, therebyresulting in that no energy loss occurs.

As another technique to prevent the above problem, there has beendisclosed a technique in which resistors are connected to respectiveLEDs in parallel (see Patent Literatures 2 and 3, for example).

FIG. 13 illustrates a circuit configuration of an LED combination lamp1000 described in Patent Literature 2. The LED combination lamp 1000 isconfigured such that a plurality of LEDs 1100 connected in series areconnected to respective resistors (Rb) 1200 in parallel. With theconfiguration, even in a case where a given LED 1100 is disconnected, acorresponding resistor 1200 works as a bypass resistor, thereby makingit possible to prevent that the other LEDs 1100 are turned off. Further,the configuration makes it possible to prevent deterioration of the LEDs1100.

However, in order that the bypass resistor carries out its purpose, itis necessary to supply, to the bypass resistor, a current sufficient toturn on the other LEDs 1100 that are not disconnected. In view of this,it is necessary to use, as the resistors 1200, resistors having a lowresistance. This arises such a problem that the current flowing throughthe bypass resistor causes large energy loss.

Further, Patent Literature 3 discloses a semiconductor light emittingdevice in which a plurality of LEDs are connected to respective variableresistors in parallel or in series so that respective currents flowingthrough the plurality of LEDs are adjustable. The semiconductor lightemitting device also has such a problem that large energy loss occursbecause an electric resistance of the variable resistors should be low.

Patent Literature 4 discloses, as an exemplary formation of resistors tobe connected to LEDs, an LED array in which a plurality of LEDs areconnected in series to respective thick-film resistive elements.

CITATION LIST Patent Literature 1

-   Japanese Patent Application Publication, Tokukaihei, No. 11-298041 A    (Publication Date: Oct. 29, 1999)

Patent Literature 2

-   Japanese Patent Application Publication, Tokukaihei, No. 11-307815 A    (Publication Date: Nov. 5, 1999)

Patent Literature 3

-   Japanese Patent Application Publication, Tokukai, No. 2007-294547 A    (Publication Date: Nov. 8, 2007)

Patent Literature 4

-   Japanese Utility Model Application Publication, Jitsukaisho, No.    63-180957 U (Publication Date: Nov. 22, 1988)

SUMMARY OF INVENTION Technical Problem

Inventors of the present invention found the following fact: In a casewhere a plurality of LEDs connected in a series-parallel connection areprovided on a substrate to achieve light emission with high luminanceand high output, electrode wiring patterns are deposited betweenadjoining LEDs so as to electrically connect the adjoining LEDs. Thiscauses such problems that luminance becomes uneven and that luminousefficiency is decreased due to absorption of light by the electrodewiring patterns.

However, Patent Literatures 1 to 4 do not describe anything about suchproblems and means for solving the problems.

Further, the configurations disclosed in Patent Literatures 1 to 3 whichemploy Zener diodes or resistors arise the following problems.

In a case where Zener diodes are used, in order to minimize theinfluence of disconnection on a package in which a plurality of LEDsconnected in series are to be mounted, a largest possible number ofZener diodes should be connected. This arises problems that the packagebecomes large in size and that a process of mounting the Zener diodes isadditionally required.

In the meantime, in order that the Zener diodes are wire-bonded, it isnecessary to dispose the Zener diodes in vicinity to LEDs and within anarea where sealing resin for sealing the LEDs is provided. However, sucha configuration is not preferable because luminance (light output) maybe decreased due to light absorption by the Zener diodes. Besides, sucha configuration that the Zener diodes are provided within the area wherethe sealing resin is provided makes it difficult to provide the LEDs inthe center.

As such, Zener diodes have a large disadvantage for mounting of LEDs ina package. Further, there are such problems that the production of theZener diodes is not easy as compared with the production of resistors,and that the Zener diodes has long-term reliability lower than that ofthe resistors.

However, even in the configuration that uses resistors, light absorptionby the resistors is caused. Further, in a case where the resistors aredisposed in an area where no sealing resin is provided, so as to preventthe light absorption by the resistors, a package should be unfavorablyenlarged in size. In addition, relatively large resistors and thick-filmresistive elements have limitations on an area in which to dispose theresistors and the thick-film resistive elements.

The present invention is accomplished in view of the above conventionalproblems. An object of the present invention is to provide a lightemitting device in which a plurality of LEDs, which are connected in aseries-parallel connection, are provided on a substrate, and which canrestrain luminance unevenness and improve luminous efficiency. Further,another object of the present invention is to provide a light emittingdevice in which a protective element(s) is provided at a portion in thelight emitting device that minimizes light absorption, thereby furtherimproving luminous efficiency.

Solution to Problem

In order to achieve the above object, a light emitting device of thepresent invention includes: a substrate; a plurality of light emittingelements provided on a primary surface of the substrate; at least oneprotective element connected in parallel with the plurality of lightemitting element; a resin frame made of a resin having a low opticaltransmittance, the resin frame being provided annularly on the primarysurface of the substrate so as to surround a mounting area in which theplurality of light emitting elements are provided; afluorescent-material-containing resin layer made of a resin containingfluorescent materials, the fluorescent-material-containing resin layerbeing provided adjacent to an inner side of the resin frame so as tocover the plurality of light emitting elements; and at least one firstlight emitting element connection electrode and at least one secondlight emitting element connection electrode, which are provided on theprimary surface of the substrate so as to face each other along a firstdirection in the primary surface, the plurality of light emittingelements having such a circuit configuration that at least two seriescircuit sections, in each of which at least two of the plurality oflight emitting elements are connected in series, are connected inparallel between the at least one first light emitting elementconnection electrode and the at least one second light emitting elementconnection electrode, the at least two series circuit sections beingaligned along a second direction orthogonal to the first direction inthe primary surface, between the at least one first light emittingelement connection electrode and the at least one second light emittingelement connection electrode, the at least two of the plurality of lightemitting elements in each of the at least two series circuit sectionsbeing aligned along the first direction, the at least one first lightemitting element connection electrode and the at least one second lightemitting element connection electrode being disposed below at least oneof the resin frame and the fluorescent-material-containing resin layer.

In the above configuration, the first light emitting element connectionelectrode and the second light emitting element connection electrode aredisposed so as to sandwich a mounting area where the light emittingelements are provided. Further, the light emitting elements in a seriescircuit section are directly wire-bonded, for example, so as to beelectrically connected to each other. Accordingly, it is unnecessary toprovide conventionally used electrode wiring patterns. Thisconfiguration reduces distances between the light emitting elements,thereby increasing a packaging density of the light emitting elements.Consequently, it is advantageously possible to restrain that lightemitted from the light emitting elements appears bright dots and torestrain in-plane luminance unevenness of the light emitting device.Furthermore, it is also advantageously possible to downsize the lightemitting device.

Further, when largest possible parts of the first light emitting elementconnection electrode and the second light emitting element connectionelectrode are disposed below the resin frame, light absorption by theseelectrodes can be restrained. In addition to this, light absorption bythe electrode wiring patterns is also reduced. This accordingly makes itpossible to improve the luminous efficiency. Further, since theprotective element is connected in parallel with the light emittingelements, it is possible to prevent deterioration of the light emittingelements, thereby allowing the light emitting device to be used for alonger term and ensuring its reliability. As a result, it is possible toprovide a light emitting device having excellent luminous efficiency andexcellent reliability.

Advantageous Effects of Invention

As described above, the light emitting device of the present inventionincludes: a substrate; a plurality of light emitting elements providedon a primary surface of the substrate; at least one protective elementconnected in parallel with the plurality of light emitting element; aresin frame made of a resin having a low optical transmittance, theresin frame being provided annularly on the primary surface of thesubstrate so as to surround a mounting area in which the plurality oflight emitting elements are provided; a fluorescent-material-containingresin layer made of a resin containing fluorescent materials, thefluorescent-material-containing resin layer being provided adjacent toan inner side of the resin frame so as to cover the plurality of lightemitting elements; and at least one first light emitting elementconnection electrode and at least one second light emitting elementconnection electrode, which are provided on the primary surface of thesubstrate so as to face each other along a first direction in theprimary surface. The light emitting device of the present invention isconfigured such that (i) the plurality of light emitting elements hassuch a circuit configuration that at least two series circuit sections,in each of which at least two of the plurality of light emittingelements are connected in series, are connected in parallel between theat least one first light emitting element connection electrode and theat least one second light emitting element connection electrode, (ii)the at least two series circuit sections are aligned along a seconddirection orthogonal to the first direction in the primary surface,between the at least one first light emitting element connectionelectrode and the at least one second light emitting element connectionelectrode, (iii) the at least two of the plurality of light emittingelements in each of the at least two series circuit sections are alignedalong the first direction, and (iv) the at least one first lightemitting element connection electrode and the at least one second lightemitting element connection electrode are disposed below at least one ofthe resin frame and the fluorescent-material-containing resin layer.

In the above configuration, the first light emitting element connectionelectrode and the second light emitting element connection electrode aredisposed so as to sandwich a mounting area where the light emittingelements are provided. Further, the light emitting elements in a seriescircuit section are directly wire-bonded, for example, so as to beelectrically connected to each other. Accordingly, it is unnecessary toprovide conventionally used electrode wiring patterns. Thisconfiguration reduces distances between the light emitting elements,thereby increasing a packaging density of the light emitting elements.Consequently, it is advantageously possible to restrain that lightemitted from the light emitting elements appears bright dots and torestrain in-plane luminance unevenness of the light emitting device.Furthermore, it is also advantageously possible to downsize the lightemitting device.

Further, when largest possible parts of the first light emitting elementconnection electrode and the second light emitting element connectionelectrode are disposed below the resin frame, light absorption by theseelectrodes can be restrained. In addition to this, light absorption bythe electrode wiring patterns is also reduced. This accordingly makes itpossible to improve the luminous efficiency. Further, since theprotective element is connected in parallel with the light emittingelements, it is possible to prevent deterioration of the light emittingelements, thereby allowing the light emitting device to be used for alonger term and ensuring its reliability. As a result, it is possible toprovide a light emitting device having excellent luminous efficiency andexcellent reliability.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1

FIG. 1 is a top view illustrating a light emitting device (withoutsealing resin) according to Embodiment 1 of the present invention.

FIG. 2

FIG. 2 is a top view illustrating the light emitting device (finishedproduct) according to Embodiment 1 of the present invention.

FIG. 3

FIG. 3 is a cross-sectional view of the light emitting device takenalong the line X-X′ of FIG. 2.

FIG. 4( a)

FIG. 4( a) is an equivalent circuit schematic illustrating a circuitconfiguration of the light emitting device of FIG. 1.

FIG. 4( b)

FIG. 4( b) is an equivalent circuit schematic illustrating a comparativeexample of FIG. 4( a).

FIG. 5

FIG. 5 is a top view illustrating a light emitting device according toEmbodiment 2 of the present invention.

FIG. 6

FIG. 6 is a top view illustrating a light emitting device according toEmbodiment 3 of the present invention.

FIG. 7

FIG. 7 is a top view illustrating a light emitting device according toEmbodiment 4 of the present invention.

FIG. 8

FIG. 8 is a top view illustrating a light emitting device according toEmbodiment 5 of the present invention.

FIG. 9

FIG. 9 is a top view illustrating a light emitting device according toEmbodiment 6 of the present invention.

FIG. 10

FIG. 10 is a top view illustrating a light emitting device according toEmbodiment 7 of the present invention.

FIG. 11

FIG. 11 is a top view illustrating a light emitting device according toEmbodiment 8 of the present invention.

FIG. 12( a)

FIG. 12( a) illustrates one embodiment of an LED electric bulb includinga light emitting device of the present invention, particularlyillustrating an appearance of a side face of the LED electric bulb.

FIG. 12( b)

FIG. 12( b) illustrates one embodiment of an LED electric bulb includinga light emitting device of the present invention, particularlyillustrating a mounting surface on which the light emitting device isprovided.

FIG. 13

FIG. 13 is an equivalent circuit schematic illustrating a circuitconfiguration of a conventional light emitting device.

DESCRIPTION OF EMBODIMENTS Embodiment 1

The following describes one embodiment of the present invention withreference to drawings. Initially explained is an entire configuration ofa light emitting device, briefly. Then, characteristic configurations, aproduction method, and the like of the light emitting device will beexplained in order.

(Entire Configuration)

FIG. 1 is a top view illustrating one exemplary configuration of a lightemitting device 100 according to the present embodiment. Morespecifically, FIG. 1 illustrates the light emitting device 100 in whichLED chips 105 and the like are provided on a primary surface of aceramic substrate 101 but they have not been resin-molded yet. FIG. 2 isa top view illustrating one exemplary configuration of the lightemitting device 100 of the present embodiment. More specifically, FIG. 2illustrates the light emitting device 100 as a finished package in whichthe LED chips 105 and the like provided on the primary surface of theceramic substrate 101 are resin-molded. Note that the resin mold (afluorescent-material-containing resin layer 109, which will be describedlater) contains fluorescent materials so that the resin mold is coloredand absorbs light. In view of this, light does not pass through theresin mold and therefore the primary surface of the ceramic substrate,on which the LED chips 105 are provided, is not observable. Further, theafter-mentioned dam resin 108 (resin frame) has a low opticaltransmittance, so that a portion, on the primary surface, that is belowthe dam resin 108 is not observable from above. FIG. 2 illustrates,through these opaque members, a mounting surface on which the LED chips105 are provided, so that the mounting surface is clearly observed.Drawings (FIG. 5 to FIG. 10) for the after-mentioned embodimentsillustrate light emitting devices in the same manner. FIG. 3 is across-sectional view of the light emitting device 100 taken along theline X-X′ of FIG. 2.

In the following description, a vertical direction in FIG. 1 and FIG. 2is referred to as a vertical direction (up-and-down direction/firstdirection) of the primary surface, and a horizontal direction in FIG. 1and FIG. 2 is referred to as a horizontal direction (left-to-rightdirection/second direction) of the primary surface. Further, an upperside in FIG. 3 is referred to as an upper side of the light emittingdevice 100, and an under side in FIG. 3 is referred to as an under sideof the light emitting device 100. Further, a view illustrating theprimary surface of the ceramic substrate 101 vertically viewed fromabove, e.g., the views of FIG. 1 and FIG. 2, is called top view (planarview).

As illustrated in FIG. 1 to FIG. 3, the light emitting device 100 of thepresent embodiment includes a ceramic substrate 101 (substrate), LEDchips 105 (light emitting elements), wires 106 (metal wires), printedresistors 107 (protective elements), a dam resin 108 (resin frame), anda fluorescent-material-containing resin layer 109.

The ceramic substrate 101 is a substrate made of ceramic. The ceramicsubstrate 101 has a rectangular outer shape in the top view. There areprovided, on a primary surface of the ceramic substrate 101, the LEDchips 105, the wires 106, the printed resistors 107, the dam resin 108,and the fluorescent-material-containing resin layer 109. Further, on theprimary surface of the ceramic substrate 101 are also provided anelectrode wiring pattern 102, an anode-side electrode land 103, and acathode-side electrode land 104.

The LED chips 105 are blue LEDs having an emission peak wavelength of450 nm, but are not limited to this. The LED chips 105 may be, forexample, ultraviolet (near-ultraviolet) LED chips having an emissionpeak wavelength of 390 nm to 420 nm. In this case, it is possible tofurther improve luminous efficiency. A plurality (44 pieces in thepresent embodiment) of the LED chips 105 are fixed on the primarysurface of the ceramic substrate 101 via a silicone resin adhesiveagent. The LED chips 105 each have a rectangular outer shape in the topview. Each of the LED chips 105 is provided with an anode electrode anda cathode electrode (hereinafter, they may be collectively called “chipelectrodes”) on its surface such that they are opposite one another in alongitudinal direction. The LED chips 105 are wire-bonded via the wires106 so as to be electrically connected to each other. The wires 106 aremade of gold, for example.

The printed resistors 107 are thin-film resistive elements which arethinner than the LED chips 105 in thickness and which are formed in sucha manner that printed paste resistor components are sintered to befixed. The printed resistors 107 are made of ruthenium oxide (RuO₂). Theprinted resistors 107 are partially formed on the primary surface of theceramic substrate 101 so as to be connected to the LED chips 105 inparallel. In this embodiment, the printed resistors (107 a to 107 c) areprovided at 3 portions on the primary surface of the ceramic substrate101.

The dam resin 108 is a resin frame having a low optical transmittance orhaving light reflectivity, which is made of white silicone resin(translucent silicone resin (base material) including titanium oxide(TiO₂) as a light-diffusion filler). The dam resin 108 is providedannularly so as to surround a mounting area where the LED chips 105 areprovided. The dam resin 108 has, in the top view, a rectangular shapehaving 4 rounded corners. The material of the dam resin 108 is notlimited to the above material, and may be, for example, acryl, urethane,epoxy, polyester, acrylonitrile butadiene styrene (ABS), polycarbonate(PC), or the like resin. Further, the color of the dam resin 108 is notlimited to white, and may be milky white, for example. When the resin iscolored in white or milky white, it is possible to set an opticaltransmittance of the resin to be low, or to allow the resin to havelight reflectivity.

The fluorescent-material-containing resin layer 109 is a sealing resinlayer formed by curing a liquid silicone resin in which particulatefluorescent materials are dispersed. The particulate fluorescentmaterials used in the present embodiment are a red fluorescent materialSrCaAlSiN₃:Eu and a green fluorescent material Ca₃(Sc,Mg)₂Si₃O₁₂:Ce. Thefluorescent-material-containing resin layer 109 is provided adjacent toan inner side of the dam resin 108 so as to cover the LED chips 105 andthe wires 106. The fluorescent-material-containing resin layer 109 has,in the top view, a rectangular shape having 4 rounded corners, inconformity to the shape of the dam resin 108. The vertical direction ofthe primary surface of the ceramic substrate 101 corresponds to ashorter-side direction of the fluorescent-material-containing resinlayer 109, while the horizontal direction of the primary surfacecorresponds to a longitudinal direction of thefluorescent-material-containing resin layer 109.

The particulate fluorescent materials are not limited to the aboveexamples, and BOSE (Ba, O, Sr, Si, Eu) or the like can be preferablyused, for example. Further, other examples of the particulatefluorescent materials that can be preferably used encompass SOSE (Sr,Ba, Si, O, Eu), YAG (Ce-activated yttrium aluminum garnet), CaAlSiN₃:Eu,α-sialon ((Ca), Si, Al, O, N, Eu), O-sialon (Si, Al, O, N, Eu), and thelike. Among these fluorescent materials selected is one(s) that allowsthe light emitting device 100 to emit light having a given color(chromaticity), in combination with emission color of the LED chips 105.

(Configuration of Electric Circuit)

FIG. 4( a) is an equivalent circuit schematic illustrating the LED chips105 and the printed resistors 107 in the light emitting device 100.

As illustrated in FIG. 4( a), in the light emitting device 100, 44 LEDchips 105 are provided in a 11×4 matrix such that 4 series circuitsections, each of which is constituted by 11 LED chips 105 connected inseries, are connected in parallel. Chip wiring in the series circuitsections is separated into 3 groups: (A) a 3-series-connection section;(B) a 5-series-connection section; and (C) a 3-series-connectionsection. More specifically, the light emitting device 100 is configuredsuch that the following 3 groups (A) to (C) are connected in series: agroup (A) having a circuit configuration in which 4 series circuitsections each including 3 LED chips 105 connected in series areconnected in parallel; a group (B) having a circuit configuration inwhich 4 series circuit sections each including 5 LED chips 105 connectedin series are connected in parallel; and a group (C) having a circuitconfiguration in which 4 series circuit sections each including 3 LEDchips 105 connected in series are connected in parallel.

The printed resistors 107 are provided in the respective groups: theseries circuit sections in the group (A) are each connected to theprinted resistor 107 a in parallel; the series circuit sections in thegroup (B) are each connected to the printed resistor 107 b in parallel;and the series circuit sections in the group (C) are each connected tothe printed resistor 107 c in parallel.

The 3 printed resistors 107 a to 107 c, which are respectively connectedto the groups A to C of series circuit sections, are set such that theratio of resistance value between the printed resistors 107 a to 107 cis equal to the ratio of the number of LED chips 105 between the groupsA to C, so that a voltage is evenly applied to the LED chips 105.

Where the resistance value of the printed resistor 107 a/107 c isrepresented by R and the resistance value of the printed resistor 107 bis represented by R′, the resistance values R and R′ are adjusted tosatisfy the following equation:

R:R′=3:5

Note that the resistance values R and R′ are set in a range from 1 MΩ to10 GΩ so as to reduce, as much as possible, a reactive current when eachof the LED chips 105 emits light.

In order to yield an effect of preventing the LED chips 105 from beingdamaged by surges, the resistance values of the printed resistors 107are preferably smaller than resistance components of reverse-biasimpedance of the LED chips 105, and are desirably not more than 10 GΩ.Further, in a case where a leak current flowing through the printedresistors 107 is restrained to the extent that a real defective productcan be found in a defect inspection process, the resistance values ofthe printed resistors 107 are preferably not less than 1 MΩ. Note thatthe defect inspection process is a process of finding a defectiveproduct by measuring a forward voltage in a microscopic area of eachfinished light emitting device. For the above reasons, it is preferablethat the resistance values (R, R′) of the printed resistors 107 a to 107c be in the range of 1 MΩ to 10 GΩ.

As such, the LED chips 105 are arrayed in groups, and a printed resistor107 is provided in each of the groups. This configuration is moreeffective in minimizing a decrease in light output when a given seriescircuit section is disconnected, as compared with a case where a singleprinted resistor 107 is connected in parallel with a series circuitsection constituted by 11 LED chips 105 connected in series.

How much the above configuration is effective is explained morespecifically, in comparison with a comparative example shown in FIG. 4(b). FIG. 4( b) is an equivalent circuit schematic in which 4 seriescircuit section, in each of which 11 LED chip 105 are connected inseries, are connected in parallel with one another and with a singleprinted resistor 107. In a case where the 11 LED chips 105 are notseparated into groups, but directly connected in series, as illustratedin FIG. 4( b), if a merely single LED chip 105 causes an open defect, nocurrent flows through all of the 11 LED chips 105, thereby resulting inthat none of the 11 LED chip 105 emits light.

In contrast, as illustrated in FIG. 4( a), in a case where 11 LED chips105 are connected by separating (sorting) them into groups of a 3-seriesconnection group, a 5-series connection group, and another 3-seriesconnection group, if one of 3 LED chips 105 in the 3-series connectiongroup is open-defective, no current flows through all of the 3 LED chips105 in the group. However, remaining 8 LED chips 105 in the other groupsstill emit light. Further, if one of 5 LED chips 105 in the 5-seriesconnection group is open-defective, no current flows through all of the5 LED chips 105 in the group, but remaining 6 LED chips 105 in the othergroups still emit light. In view of this, the configuration shown inFIG. 4( a) yields a significant effect of preventing such a problem thatall the 11 LED chips do not emit light, unlike in the case of FIG. 4(b).

Further, the printed resistors 107 a to 107 c are connected to the LEDchips 105 in parallel, thereby making it possible to preventdeterioration of the LED chips 105. This allows the LED chips 105 to beused for a longer term and ensures their reliability. As a result, it ispossible to provide a light emitting device 100 having excellentreliability.

(Configuration of Ceramic Substrate 101)

The following deals with a configuration of the primary surface of theceramic substrate 101. As has been already described, on the primarysurface of the ceramic substrate 101 are provided the electrode wiringpattern 102, the anode-side electrode land 103, and the cathode-sideelectrode land 104.

The electrode wiring pattern 102 is a wiring pattern provided betweenthe anode-side electrode land 103 and the cathode-side electrode land104 so as to electrically connect the LED chips 105 to the anode-sideelectrode land 103 and the cathode-side electrode land 104 directly orin relays. The electrode wiring pattern 102 is made of gold (Au) anddisposed (formed) in accordance with a circuit configuration. In thepresent embodiment, the electrode wiring pattern 102 includes connectionwiring lines 102 a, 102 d, 102 g, and 102 j, anode-side electrodes(first light emitting element connection electrode) 102 b, 102 e, and102 h, and cathode-side electrodes (second light emitting elementconnection electrode) 102 c, 102 f, and 102 i.

The anode-side electrode 102 b and the cathode-side electrode 102 c areelectrodes provided for connecting LED chips 105 corresponding to thegroup (A) illustrated in FIG. 4( a). The anode-side electrode 102 b iselectrically connected to the LED chips 105 via wires 106, while thecathode-side electrode 102 c is electrically connected to the LED chips105 via wires 106. The anode-side electrode 102 b and the cathode-sideelectrode 102 c sandwich a group of the LED chips 105 corresponding tothe group (A), and disposed so as to face each other along theshorter-side direction of the fluorescent-material-containing resinlayer 109. The anode-side electrode 102 b, the cathode-side electrode102 c, and the group of the LED chips 105 corresponding to the group (A)constitute a group L1.

The anode-side electrode 102 e and the cathode-side electrode 102 f areelectrodes for connecting LED chips 105 corresponding to the group (B)illustrated in FIG. 4( a). The anode-side electrode 102 e iselectrically connected to the LED chips 105 via wires 106, while thecathode-side electrode 102 f is electrically connected to the LED chips105 via wires 106. The anode-side electrode 102 e and the cathode-sideelectrode 102 f sandwich a group of the LED chips 105 corresponding tothe group (B), and disposed so as to face each other along theshorter-side direction of the fluorescent-material-containing resinlayer 109. The anode-side electrode 102 e, the cathode-side electrode102 f, and the group of the LED chips 105 corresponding to the group (B)constitute a group L2.

The anode-side electrode 102 h and the cathode-side electrode 102 i areelectrodes provided for connecting LED chips 105 corresponding to thegroup (C) illustrated in FIG. 4( a). The anode-side electrode 102 h iselectrically connected to the LED chips 105 via wires 106, while thecathode-side electrode 102 i is connected to the LED chips 105 via wires106. The anode-side electrode 102 h and the cathode-side electrode 102 isandwich a group of the LED chips 105 corresponding to the group (C),and disposed so as to face each other along the shorter-side directionof the fluorescent-material-containing resin layer 109. The anode-sideelectrode 102 h, the cathode-side electrode 102 i, and the group of theLED chips 105 corresponding to the group (C) constitute a group L3.

The groups L1 to L3 are aligned along the longitudinal direction of thefluorescent-material-containing resin layer 109. The anode-sideelectrodes 102 b, 102 e, and 102 h are aligned on the upper side of FIG.1, i.e., disposed above the mounting area where the LED chips 105 areprovided. The cathode-side electrodes 102 c, 102 f, and 102 i arealigned on the under side of FIG. 1, i.e., disposed below the mountingarea where the LED chips 105 are provided.

The connection wiring lines 102 a, 102 d, 102 g, and 102 j areinterconnection wiring lines provided between the anode-side electrodeland 103 and the cathode-side electrode land 104 so as to connect thegroups L1 to L3 in series. The connection wiring line 102 a electricallyconnects the anode-side electrode land 103 to the anode-side electrode102 b. The connection wiring line 102 d electrically connects thecathode-side electrode 102 c to the anode-side electrode 102 e. Theconnection wiring line 102 g electrically connects the cathode-sideelectrode 102 f to the anode-side electrode 102 h. The connection wiringline 102 j electrically connects the cathode-side electrode 102 i to thecathode-side electrode land 104. Each of the connection wiring lines 102a, 102 d, 102 g, and 102 j is disposed along the shorter-side directionof the fluorescent-material-containing resin layer 109 and on aperipheral area of a corresponding one of the mounting areas where thegroups L1 to L3 are provided.

The anode-side electrode land 103 and the cathode-side electrode land104 are electrodes connectable to an external voltage supply of thelight emitting device 100. The anode-side electrode land 103 and thecathode-side electrode land 104 are made of silver (Ag) platinum (Pt).The anode-side electrode land 103 is provided near a corner (at theupper right in FIG. 1) of the primary surface of the ceramic substrate101. The cathode-side electrode land 104 is provided near another corner(at the lower left in FIG. 1) of the primary surface of the ceramicsubstrate 101, which corner is diagonally opposite the corner where theanode-side electrode land 103 is provided. That is, the anode-sideelectrode land 103 and the cathode-side electrode land 104 are disposeddiagonally on the primary surface of the ceramic substrate 101.

The connection wiring lines 102 a and 102 j are extended to be connectedto the anode-side electrode land 103 and the cathode-side electrode land104, respectively. On this account, parts of the connection wiring lines102 a and 102 j are not covered with the dam resin 108 and thefluorescent-material-containing resin layer 109. In view of this, it ispreferable to provide insulation protection films 110 on these parts ofthe connection wiring lines 102 a and 102 j, which parts are uncoveredwith the dam resin 108 and the fluorescent-material-containing resinlayer 109.

As such, on the primary surface of the ceramic substrate 101, theanode-side electrode (102 b, 102 e, 102 h) and the cathode-sideelectrode (102 c, 102 f, 102 i) are disposed so as to sandwich acorresponding mounting area where corresponding LED chips 105 areprovided. Further, in respective mounting areas of the LED chips 105 ofthe groups L1 to L3 (groups (A) to (C)), the LED chips 105 are directlywire-bonded so as to be electrically connected to each other, as will bedescribed later. This configuration accordingly does not requireelectrode wiring patterns that are conventionally used. The connectionwiring lines 102 a, 102 d, 102 g, and 102 j are disposed on peripheralareas of the respective groups of the LED chips 105 of the groups L1 toL3 (groups (A) to (C)), so as not to cross the mounting areas where thegroups of LED chips 105 are provided.

As a result, it is possible to reduce distances between the LED chips105, thereby increasing a packaging density of the LED chips 105. Thisrestrains that light emitted from the LED chips 105 appears bright dots,and further restrains in-plane luminance unevenness the light emittingdevice 100. Further, the configuration allows the light emitting device100 to be downsized.

Further, the anode-side electrode 102 e and the cathode-side electrode102 f are partially provided below the dam resin 108. Accordingly, it ispossible to restrain light absorption by the anode-side electrode 102 eand the cathode-side electrode 102 f. Thus, when a largest possible partof the electrode wiring pattern 102 is disposed below the resin frame,it is possible to restrain light absorption by these electrodes.Further, in the configuration, the number of connection wiring lines isreduced as much as possible. This can improve luminous efficiency.

The connection wiring lines (especially, the connection wiring lines 102d and 102 g) are preferably provided to have widths narrower than thoseof the anode-side electrodes 102 b, 102 e, and 102 h and thecathode-side electrodes 102 c, 102 f, and 102 i, so as to be reduced inarea. One reason is as follows: The fluorescent-material-containingresin layer 109 may sometimes be stripped at an interface between thefluorescent-material-containing resin layer 109 and the ceramicsubstrate 101 and at an interface between thefluorescent-material-containing resin layer 109 and the connectionwiring lines. This is because during a light-emission period and ano-light-emission period, a difference of adhesive property and adifference of coefficient of thermal expansion are caused between (a)the fluorescent-material-containing resin layer 109 and (b) a respectiveof the ceramic substrate 101 and the connection wiring lines, due tothermal burdens, such as heat cycle, applied thereto. However, with theabove configuration, it is possible to restrain the stripping of thefluorescent-material-containing resin layer 109. Further, the aboveconfiguration can reduce light loss due to connection wiring lines,which are disposed across the mounting surface, and restrain in-planeluminance unevenness of the light emitting device.

Further, the anode-side electrodes 102 b, 102 e, and 102 h are disposedon a same side on the mounting surface, while the cathode-sideelectrodes 102 c, 102 f, and 102 i are provided on another same side onthe mounting surface. This allows chip electrodes of the LED chips 105to be disposed along a given polar direction, when the LED chips 105 areprovided on the mounting surface. It is accordingly possible to die-bondthe LED chips 105 without changing the polar direction of their chipelectrodes, i.e., without changing the orientation of the LED chips 105,thereby simplifying a die-bonding device/process for die-bonding the LEDchips 105.

The anode-side electrode 102 b and 102 h are positioned at a more innerside than the anode-side electrode 102 e, and the cathode-sideelectrodes 102 c and 102 i are positioned at a more inner side than thecathode-side electrode 102 f. As such, a distance between the anode-sideelectrode 102 b and the cathode-side electrode 102 c and a distancebetween the anode-side electrode 102 h and the cathode-side electrode102 i are narrower than a distance between the anode-side electrode 102e and the cathode-side electrode 102 f. This increases likelihood ofwire-bonding areas for the anode-side electrodes 102 b and 102 h and thecathode-side electrode 102 c and 102 i, and accordingly improvesworkability of wire bonding. Note however that in a case where adecrease in light absorption by the electrode wiring pattern 102 isprioritized, the electrode wiring pattern may not be formed in thismanner.

(Layout of LED Chips 105)

Next will be explained about how to arrange the LED chips 105. Asdescribed above, 44 LED chips 105 are divided into 3 groups L1 to L3, inconsideration of the aforementioned circuit configuration and mountingarea.

In the group L1, there are provided, between the anode-side electrode102 b and the cathode-side electrode 102 c, 4 series circuit sections,which are aligned along the longitudinal direction of thefluorescent-material-containing resin layer 109 so as to be electricallyconnected in parallel with each other. Each of the series circuitsections is configured such that 3 LED chips 105 are arrayed in seriesalong the shorter-side direction of the fluorescent-material-containingresin layer 109 so as to be electrically connected in series with eachother.

In the group L2, there are provided, between the anode-side electrode102 e and the cathode-side electrode 102 f, 4 series circuit sections,which are aligned along the longitudinal direction of thefluorescent-material-containing resin layer 109 so as to be electricallyconnected in parallel with each other. Each of the series circuitsections is configured such that 5 LED chips 105 are arrayed in seriesalong the shorter-side direction of the fluorescent-material-containingresin layer 109 so as to be electrically connected in series with eachother.

In the group L3, there are provided, between the anode-side electrode102 h and the cathode-side electrode 102 i, 4 series circuit sections,which are aligned along the longitudinal direction of thefluorescent-material-containing resin layer 109 so as to be electricallyconnected in parallel with each other. Each of the series circuitsections is configured such that 3 LED chips 105 are arrayed in seriesalong the shorter-side direction of the fluorescent-material-containingresin layer 109 so as to be electrically connected in series with eachother.

The 3 groups L1 to L3 are aligned such that a smaller number of LEDchips 105 are provided at corner sections of thefluorescent-material-containing resin layer 109 so that the mountingarea is reduced in total. That is, the group L2 is positioned around acenter of the primary surface of the ceramic substrate 101. The groupsL1 and L3 are positioned at respective sides of the group L2 along thelongitudinal direction of the fluorescent-material-containing resinlayer 109. The number of LED chips 105 in each of the groups L1 and L3is smaller than that of the group 2. On this account, the groups L 1 andL3 are provided with sufficient room so as to conform to the shape ofthe fluorescent-material-containing resin layer 109 and to ensure anelectrode wiring pattern area having a wire-bonding area.

Such a configuration in which the plurality of LED chips 105 areprovided in 3 groups (L1 to L3) makes it possible to form the mountingarea where the LED chips 105 are provided, in a rectangular shape assmall as possible. Further, the configuration makes it possible toreduce an area for the layout on the ceramic substrate 101, includingthe anode-side electrode land 103 and the cathode-side electrode land104. As a result, it is possible to realize a light emitting device 100that is more downsized.

Further, in each of the groups L1 to L3, each of the series circuitsections is configured such that adjoining LED chips 105 are connectedby wire-bonding in such a manner that a cathode electrode of one of theadjoining LED chips 105 is directly connected to an anode electrode ofthe other one of the adjoining LED chip 105. As such, in each of thegroups L1 to L3, no electrode wiring pattern 102 for interconnectingadjoining LED chips 105 is provided, thereby resulting in that distancesbetween the adjoining LED chips 105 are reduced and the packagingdensity of the LED chips 105 can be increased.

Further, all the LED chips 105 are aligned in the same orientation andeach of the LED chips 105 is disposed such that its cathode electrodeand anode electrode face each other along the shorter-side direction ofthe fluorescent-material-containing resin layer 109. That is, all theLED chips 105 are configured such that their chip electrodes aredisposed in the same orientation, and aligned such that theirlongitudinal directions on their top surfaces are along the shorter-sidedirection of the fluorescent-material-containing resin layer 109. In thepresent embodiment, the anode electrode is positioned on an upper sideof an LED chip (see FIG. 1). This configuration makes it possible todie-bond the LED chips 105 without changing the polar directions oftheir chip electrodes, i.e., without changing the orientation of the LEDchips 105.

(Layout of Printed Resistors 107)

Next will be explained about how to arrange the printed resistors 107.The printed resistors 107 are provided as printed resistors 107 a to 107c for the respective groups (L1, L2, and L3).

The printed resistor 107 a is electrically connected to the connectionwiring line 102 a and the anode-side electrode 102 e. Further, theprinted resistor 107 a is provided in alignment with the anode-sideelectrode 102 e. The printed resistor 107 b is electrically connected tothe cathode-side electrode 102 c and the cathode-side electrode 102 f.Further, the printed resistor 107 b is provided in alignment with theconnection wiring line 102 d. The printed resistor 107 c is electricallyconnected to the cathode-side electrode 102 f and the connection wiringline 102 j. Further, the printed resistor 107 c is provided in alignmentwith the cathode-side electrode 102 f.

The printed resistors 107 a to 107 c are provided on a periphery of themounting area where the LED chips 105 are provided. Moreover, most partsof the printed resistors 107 a and 107 c and a part of the printedresistor 107 b are disposed below the dam resin 108 having a low opticaltransmittance.

As such, largest possible parts of the printed resistors 107 a to 107 care provided below the dam resin 108 so as to be covered with the damresin 108, thereby restraining light absorption by the printed resistors107 a to 107 c as much as possible. Accordingly, it is possible toprevent a decrease of light output of the light emitting device 100.

(Configuration of Dam Resin 108)

The following describes the configuration of the dam resin 108, morespecifically.

As illustrated in FIG. 3, a cross section of the dam resin 108 has adome shape (upper side<lower side) that projects upward. The shape ofthe cross section causes light emitted from the LED chips 105 in alateral direction, especially toward a direction of the dam resin 108,to reflect off the dam resin 108. This yields an effect that the lightcan be easily directed toward a front surface of the substrate.

The shape of the cross section of the dam resin 108 is not limited tothis. Further, in order to minimize an area where thefluorescent-material-containing resin layer 109 is to be formed, it ispreferable that the dam resin 108 be provided so as to cover a part ofthe electrode wiring pattern 102 and parts of the wires 106, too.

(Configuration of Fluorescent-Material-Containing Resin Layer 109)

Next will be explained about the configuration of thefluorescent-material-containing resin layer 109.

As illustrated in FIG. 3, a cross section of thefluorescent-material-containing resin layer 109 has a dome shape (upperside<lower side) that projects upward. That is, thefluorescent-material-containing resin layer 109 appears to be formed insuch a shape that an oval sphere is partially cut out. The lightemitting device 100 is configured such that a dome-shaped surface(spherical shape) of the fluorescent-material-containing resin layer 109is a light-emission surface of the light emitting device 100. In view ofthis, when the light-emission surface is formed in the above shape assuch, it is possible to cause light from the LED chips 105 and lightfrom the fluorescent materials to be outputted efficiently. As a result,it is possible to yield an effect of improving luminous efficiency.

Further, the shape of the surface of the fluorescent-material-containingresin layer 109 is not limited to the aforementioned dome shape. It isalso possible to adjust a degree of how much thefluorescent-material-containing resin layer 109 is projecting, dependingon its viscosity. For example, the surface of thefluorescent-material-containing resin layer 109 may be formed in analmost-flat shape having a slight recess in its center portion or in aslightly projecting shape having a smooth curved surface.

(Production Method)

The following briefly describes how to produce the light emitting device100 having the aforementioned configuration.

The light emitting device 100 is produced in such a manner that a groupof a plurality of light emitting devices is collectively formed on asingle large ceramic substrate, and the single large ceramic substrateis diced along peripheries of individual light emitting devices at theend of the production process so as to separate the individual lightemitting devices. Thus, individual light emitting devices 100 areproduced.

Initially, on a primary surface of a ceramic substrate 101 are formed anelectrode wiring pattern 102, an anode-side electrode land 103, and acathode-side electrode land 104. Then, printed resistors 107 are formedon the primary surface of the ceramic substrate 101 by printing, forexample. After that, LED chips 105 are die-bonded on the primary surfaceof the ceramic substrate 101, and then wire-bonded by wires 106.

Subsequently, a dam resin 108 is formed on the primary surface of theceramic substrate 101. More specifically, the dam resin 108 is formed byplotting liquid white silicone resin (containing a light-diffusionfiller (TiO₂)) by use of a dispenser. The dam resin is cured at 120° C.for 60 minutes.

Subsequently, a dome-shaped fluorescent-material-containing resin layer109 is formed on the primary surface of the ceramic substrate 101 asillustrated in FIG. 3. More specifically, thefluorescent-material-containing resin layer 109 is filled, by use of adispenser, into an area surrounded by the dam resin 108. Lastly, theceramic substrate 101 is divided into individual light emitting devices100. Thus, the light emitting device 100 can be produced. With the useof the production method, it is possible to easily produce the lightemitting device 100 at a low cost.

Instead of the dam resin 108, a shaped sheet prepared in the shape ofthe dam resin 108 may be attached on the primary surface of the ceramicsubstrate 101. The shaped sheet is prepared by forming fluoro-rubber orsilicone rubber into a sheet, and may have an adhesive sheet on one sidethereof that is to be attached to the primary surface of the ceramicsubstrate 101.

Further, in the present embodiment, the dam resin 108 is ensured to beincorporated into the light emitting device 100. However, in a casewhere the shaped sheet is attached to the primary surface of the ceramicsubstrate 101, the shaped sheet may be removed eventually depending onan intended light distribution characteristic of the light emittingdevice 100.

Further, how to form the fluorescent-material-containing resin layer 109is also not limited to the aforementioned method in which the materialof the fluorescent-material-containing resin layer 109 is filled, by useof a dispenser, into the area surrounded by the dam resin 108. Forexample, instead of using the dam resin 108, thefluorescent-material-containing resin layer 109 may be formed bycollectively sealing the LED chips 105 and the electrode wiring pattern102 by a translucent resin containing fluorescent materials, by means ofcompression molding or transfer molding by use of a mold or the like.

The aforementioned production method of the light emitting device 100makes it possible to easily form the dam resin 108 and thefluorescent-material-containing resin layer 109 on the printed resistors107. This allows the printed resistors 107 to be highly flexiblydisposed in desirable areas. That is, the printed resistors 107 can bedisposed in vicinity to the LED chips 105 and below the dam resin 108and the fluorescent-material-containing resin layer 109.

In the above production method, the LED chips 105 are initially mounted,wire-bonding is carried out, and then the dam resin 108 is formed.However, the order of the processes is not limited to this, and may be,for example, such that the dam resin 108 is formed first, the LED chips105 are mounted, and finally wire-bonding is carried out.

Exemplary dimensions of the members provided in the light emittingdevice 100 having the aforementioned configuration are described below.

Ceramic Substrate 101: overall size of 12 mm×15 mm, 1 mm in thickness

Electrode Wiring Pattern 102: 300 μm in width and 10 μm in thickness

Anode-side Electrode Land 103 and Cathode-side Electrode Land 104: 1.4mm in diameter, 2 mm of linear portion, 20 μm in thickness

LED chip 105: 240 μm in width, 400 μm in length, 80 μm in height

Dam Resin 108: 0.7 mm in ring width, overall size of 6.9 mm×7.9 mm, R ofcorner portion=2 mm

These dimensions are merely an example.

Modified Example

The aforementioned light emitting device 100 uses a ceramic substrate101, but is not limited to this. The light emitting device 100 may useother substrates instead. For example, a metal core substrate includinga metal substrate on whose surface an insulating layer is provided maybe used. In this case, the insulating layer is formed only in an areawhere the printed resistors 107 and the electrode wiring pattern 102 areto be formed, so that a plurality of LED chips 105 are directly providedon the metal substrate surface.

Further, the outer shape of the ceramic substrate 101 is not limited toa rectangular shape. Further, the vertical direction (up-and-downdirection/first direction) and the horizontal direction (left-to-rightdirection/second direction) on the primary surface is not determinedbased on the outer shape of the primary surface, but is determineddepending on relative positional relationship of the electrode wiringpattern 102, the LED chips 105, and the like.

Further, the LED chip 105 is rectangle in the top view, but may besquare. The LED chip 105 may be, for example, an LED chip that is 300micrometers square and 100 micrometers high. Further, how to mount LEDchips 105 is not limited to the wire-bonding, and may be, for example,flip-chip bonding (not shown).

Further, the number of LED chips 105, how the LED chips 105 are to beseparated in groups, and how the circuit is to be configured are notlimited to those which have been described above. For example, in a casewhere the number of LED chips 105 is 44 as exemplified above, it is alsopossible to divide the LED chips 105 into the following groups: “a group(A) in which each series circuit section includes 4 LED chips connectedin series; a group (B) in which each series circuit section includes 4LED chips connected in series; and a group (C) in which each seriescircuit section includes 4 LED chips connected in series”. Such aconfiguration also yields the same effect. That is, the plurality of LEDchips 105 may be provided in any manner as long as at least 2 seriescircuit sections, in each of which at least 2 LED chips 105 areconnected in series, are connected in parallel.

Further, although the flexibility to the mounting area is decreased, aZener diode may be used instead of the printed resistor 107. In thiscase, it is possible to use a plurality of Zener diodes according to thenumber of LED chips 105 connected in series in a series connectionsection.

Next will be explained about other embodiments of the present invention,based on drawings. Configurations other than a configuration that willbe explained below in each embodiment are the same as in Embodiment 1.Further, for convenience of explanation, in each embodiment, a memberhaving the same function as its corresponding member shown in thedrawings of Embodiment 1 has the same reference sign, and will not beexplained here.

Embodiment 2

FIG. 5 is a top view illustrating one exemplary configuration of a lightemitting device 200 of the present embodiment.

The light emitting device 200 of the present embodiment is differentfrom the light emitting device 100 of Embodiment 1 in terms of how theelectric circuit is configured. Except for this point, the lightemitting device 200 has a configuration equivalent of the light emittingdevice 100 of Embodiment 1.

As illustrated in FIG. 5, the light emitting device 200 has a circuitconfiguration in which 14 series circuit sections, in each of which 7LED chips 105 are linearly aligned so as to be connected in series, areconnected in parallel. In other words, 98 LED chips 105 in total, whichare connected in a series-parallel connection (i.e., 7 series-connectedLED chips per series circuit section×14 parallel-connected seriescircuit sections), are provided on a primary surface of a ceramicsubstrate 101.

The electrode wiring pattern 102 is constituted by an anode-sideelectrode 102 k and a cathode-side electrode 102 l. The anode-sideelectrode 102 k and the cathode-side electrode 102 l are electricallyconnected with the LED chips 105 via wires 106. The anode-side electrode102 k and the cathode-side electrode 102 l are disposed so as tosandwich a group of the LED chips 105 and to face each other along ashorter-side direction of a fluorescent-material-containing resin layer109 (a direction along which the LED chips 105 are linearly aligned).

A single printed resistor 107 is provided so as to be connected inparallel with the series circuit sections. That is, the printed resistor107 is connected to the anode-side electrode 102 k and the cathode-sideelectrode 102 l. The printed resistor 107 is provided vertically to theanode-side electrode 102 k and the cathode-side electrode 102 l, in thetop view.

Similarly to the light emitting device 100 of Embodiment 1, the lightemitting device 200 has effects of restraining, by the printed resistor107, defection due to disconnection in a series circuit sectionconstituted by LED chips 105 and minimizing a decrease in light outputwhen a series circuit section constituted by LED chips 105 isdisconnected.

Embodiment 3

FIG. 6 is a top view illustrating one exemplary configuration of a lightemitting device 300 of the present embodiment.

The light emitting device 300 of the present embodiment is differentfrom the light emitting device 100 of Embodiment 1 in terms of amounting direction (polar direction) of LED chips 105 and a wiringdirection of wires 106 corresponding to the mounting direction. Exceptfor this point, the light emitting device 300 has a configurationequivalent of the light emitting device 100 of Embodiment 1.

As illustrated in FIG. 6, the light emitting device 300 is constitutedby the following groups L1 to L3: (i) the group L1 is configured suchthat 2 series circuit sections each including 4 LED chips 105 connectedin series are connected in parallel; (ii) the group L2 is configuredsuch that 3 series circuit sections each including 8 LED chips 105connected in series are connected in parallel; and (iii) the group L3 isconfigured such that 2 series circuit sections each including LED chips105 connected in series are connected in parallel. That is, 40 LED chips105 in total, which are connected in a series-parallel connection, areprovided on a primary surface of a ceramic substrate 101.

Further, each of the LED chips 105 is aligned such that its longitudinaldirection is consistent with a longitudinal direction of afluorescent-material-containing resin layer 109. That is, the LED chips105 in the light emitting device 300 are rotated by 90° with respect tothe orientation direction of the LED chips 105 in the light emittingdevice 100. Wires 106 are provided obliquely in conformity to thealignment of the LED chips 105.

In the light emitting device 300, in addition to the same effects as thelight emitting device 100 of Embodiment 1, it is possible to reduce adam resin 108 in size, thereby allowing the light emitting device 100 toapproximate a point light source. Further, in the light emitting device300, it is possible to broad a space between the mounting area of LEDchips 105 and a respective of the mounting areas of an anode-sideelectrode land 103 and an cathode-side electrode land 104. This yieldssuch an effect that the LED chips 105 are easily bonded.

Note that the light emitting device 300 requires a more amount of wiresthan in the light emitting device 100 because the wires 106 becomelonger than that in the light emitting device 100. In view of this, theconfiguration of the light emitting device 100 is more preferable thanthe configuration of the light emitting device 300, as a whole.

Embodiment 4

FIG. 7 is a top view illustrating one exemplary configuration of a lightemitting device 400 of the present embodiment.

The light emitting device 400 of the present embodiment is differentfrom the light emitting device 100 of Embodiment 1 in how to configureLED chips 105 and wires 106 in the group L2. Except for this point, thelight emitting device 400 has a configuration equivalent of the lightemitting device 100 of Embodiment 1.

As illustrated in FIG. 7, the light emitting device 400 is configuredsuch that in a group L2, 3 series circuit sections each including 8 LEDchips 105 connected in series are connected in parallel. In view ofthis, in the light emitting device 400, 48 LED chips 105 in total, whichare connected in a series-parallel connection, are provided on a primarysurface of a ceramic substrate 101. Each of the LED chips 105 in thegroup L2 is aligned such that its longitudinal direction is consistentwith a longitudinal direction of a fluorescent-material-containing resinlayer 109. Accordingly, wires 106 are provided obliquely in conformityto the alignment of the LED chips 105.

In the light emitting device 400, it is possible to provide a largernumber of LED chips 105 within an area surrounded by a dam resin 108having the same size as the dam resin 108 provided in the light emittingdevice 300 of Embodiment 3. In this way, in which orientation directionLED chips 105 are aligned may vary between groups so that an intendednumber of LED chips can be provided.

Embodiment 5

FIG. 8 is a top view illustrating one exemplary configuration of a lightemitting device 500 of the present embodiment.

The light emitting device 500 of the present embodiment is differentfrom the light emitting device 100 of Embodiment 1 in that the lightemitting device 500 includes 40 LED chips 105 and 4 LED chips 105′,while the light emitting device 100 includes 44 LED chips 105. Exceptfor this point, the light emitting device 500 has a configurationequivalent of the light emitting device 100 of Embodiment 1.

The LED chip 105′ is smaller than the LED chip 105 in chip size (forexample, a square of 0.3 mm×0.3 mm in the top view). On the whole, asillustrated in FIG. 8, the LED chips 105′ are placed at 4 corners of amounting area where the LED chips 105 are provided. That is, the LEDchips 105′ are provided at 4 corners of an area where afluorescent-material-containing resin layer 109 is provided, which 4corners are placed proximal to a dam resin 108,

As such, the light emitting device 500 includes the LED chips 105′placed at the 4 corners of the area where thefluorescent-material-containing resin layer 109 is provided, which 4corners are proximal to the dam resin 108. The LED chips 105′ aresmaller in size than the LED chips 105 that are provided in the areaother than the 4 corners. This configuration can reduce, in size, aframe made of the dam resin 108, thereby making it possible to reduce alight emission area.

Embodiment 6

FIG. 9 is a top view illustrating one exemplary configuration of a lightemitting device 600 of the present embodiment.

The light emitting device 600 of the present embodiment is differentfrom the light emitting device 100 of Embodiment 1 in the shapes of thedam resin 108 and the fluorescent-material-containing resin layer 109.Except for this point, the light emitting device 600 has a configurationequivalent of the light emitting device 100 of Embodiment 1.

As illustrated in FIG. 9, in the light emitting device 600, a dam resin108 has an annular shape in the top view. A large part of the dam resin108 is formed on printed resistors 107. Afluorescent-material-containing resin layer 109 is provided along theshape of the dam resin 108 so as to have a circular shape in the topview.

In the light emitting device 600, the fluorescent-material-containingresin layer 109 is formed in a circular shape as such, thereby causinglight emitted from LED chips 105 to easily output in all directions,uniformly. Further, with the above configuration, the light emittingdevice 600 can be easily applied to a general-purpose lightingapparatus, and such a general-purpose lighting apparatus to which thelight emitting device 600 is applied can be easily designed.

Embodiment 7

FIG. 10 is a top view illustrating one exemplary configuration of alight emitting device 700 of the present invention.

The light emitting device 700 of the present invention is different fromthe light emitting device 100 of Embodiment 1 in terms of a region wherethe printed resistor 107 b is provided and a region where the dam resin108 is provided. Except for this point, the light emitting device 700has a configuration equivalent of the light emitting device 100 ofEmbodiment 1.

As illustrated in FIG. 10, in the light emitting device 700, a printedresistor 107 b is formed along a curve of a dam resin 108 so as to bedisposed below the dam resin 108. The dam resin 108 is formed ratherwide so as to cover all printed resistors 107 a to 107 c.

In the light emitting device 700, all the printed resistors 107 a to 107c are covered with the dam resin 108 and disposed at positions that donot cause the printed resistors 107 a to 107 c to diminish other opticalcharacteristics. This makes it possible to minimize loss of luminousefficiency due to light absorption by the printed resistors 107 a to 107c.

Embodiment 8

FIG. 11 is a top view illustrating one exemplary configuration of alight emitting device 800 of the present embodiment.

The light emitting device 800 of the present embodiment is differentfrom the light emitting device 100 of Embodiment 1 in terms of in whichorientation direction the LED chips 105 in the group L2 are provided.Except for this point, the light emitting device 800 has a configurationequivalent of the light emitting device 100 of Embodiment 1. In FIG. 11,a dam resin 108 and a fluorescent-material-containing resin layer 109are not illustrated, but these members are also provided in the lightemitting device 800 in the same manner as in FIG. 2.

As illustrated in FIG. 11, in the light emitting device 800, LED chips105 in a group L2 are aligned in such an orientation that their cathodeelectrodes are placed on upper sides of the LED chips 105. That is, theLED chips 105 in the group L2 in the light emitting device 800 arerotated by 180° with respect to the orientation direction of the LEDchips 105 in the group L2 in the light emitting device 100. Accordingly,an electrode wiring pattern 102 is provided in the light emitting device800 such that an anode-side electrode 102 e and a cathode-side electrode102 f are positioned in an inverse manner to the light emitting device100 of Embodiment 1. Further, printed resistors 107 have the sameelectric circuit configuration as the light emitting device 100, butthey are formed on different positions from those in the light emittingdevice 100.

In the light emitting device 800, it is not necessary that (a) aconnection wiring line 102 d for connecting a group L1 to the group L2be disposed therebetween and (b) a connection wiring line 102 g forconnecting the group L2 to a group L3 be disposed therebetween.Accordingly, it is possible to reduce loss of light absorption by thesewiring lines.

The light emitting devices according to Embodiments 1 to 8 describedabove each essentially include a printed resistor(s) 107. However, in acase where the light emitting device according to any of Embodiments 1to 8 is used for a purpose that does not require an electrostaticdischarge resistance so much or in a case where each LED chip 105 itselfhas a high electrostatic discharge resistance, the light emitting deviceaccording to any of Embodiments 1 to 8 may not include the printedresistor(s) 107.

Embodiment 9

The present embodiment deals with an electronics device including any ofthe light emitting devices described in Embodiments 1 to 8.

For example, there is an illuminating device including: (i) a base boardhaving a voltage supply circuit on its back side, and a radiator plateintegrated therein; and (ii) a light emitting device according to anyone of Embodiment 1 to 8, which is provided on the base board. The lightemitting device is configured such that the anode-side electrode land103 and the cathode-side electrode land 104 are electrically connected,via external wiring lines or the like, to an anode electrode land and acathode electrode land of the base board, respectively. A top surface ofthe light emitting device is covered with either a case having alight-diffusing function or a transparent case.

Further, the number of light emitting devices to be provided in theilluminating device is not limited to 1. For example, the illuminatingdevice may be a fluorescent illuminating device constituted by aplurality of light emitting devices. In this case, the plurality oflight emitting devices are disposed such that one sides of rectangularceramic substrates 101 thereof are aligned in parallel or one diagonalsof the rectangular ceramic substrates 101 are aligned in line. Note thatjust a single light emitting device may be provided in an illuminatingdevice so that the illuminating device serves as an electric-bulbilluminating device.

The following deals with a configuration of an LED electric bulbincluding a light emitting device according to any one of Embodiment 1to 8, as a concrete example of the illuminating device. FIG. 12( a) andFIG. 12( b) illustrate one exemplary configuration of an LED electricbulb 900. FIG. 12( a) illustrates an appearance of a side face of theLED electric bulb 900. FIG. 12( b) illustrates a mounting surface onwhich a light emitting device 909 is provided.

As illustrated in FIG. 12( a) and FIG. 12( b), the LED electric bulb 900is configured such that a base plate 904 is fixed, by screws 905, to aradiation fin 902 fastened onto a mouth ring 901, and a lens dome 903containing a scattering material is provided so as to cover the baseplate 904. The mouth ring 901 is a metal part of the electric bulb whichmetal part is screwed into a socket. A size of the mouth ring 901 may bepreferably E26, E17, or the like. In particular, the light emittingdevices according to Embodiments 1 to 8 can be produced with a smallsurface area, such as 15 mm×12 mm. In view of this, the size of themouth ring 901 is preferably E17.

On the base plate 904 is provided a light emitting device 909. The lightemitting device 909 is fixed by tap pins 906. As the light emittingdevice 909, any of the light emitting devices according to Embodiments 1to 8 described above can be used. The light emitting device 909 includesan anode-side electrode land 103 and a cathode-side electrode land 104,which are electrically connected to external wiring lines (an anode wireconnection 907 and a cathode wire connection 908).

By arranging the LED electric bulb 900 to include the light emittingdevice 909, it is possible to restrain luminance unevenness and toimprove luminous efficiency. As a result, the LED electric bulb 900serves as a very excellent illuminating device.

Further, it is also possible to form a planar light source in which aplurality of light emitting devices according to any one of Embodiments1 to 8 are disposed on a housing substrate in a matrix manner. In thiscase, when each of the light emitting devices is provided with anexternal lens for adjusting a light distribution characteristic, or whena fluorescent-material-containing resin layer 109 in each of the lightemitting devices is formed in a projecting shape, as illustrated in FIG.3, so as to have a lens function, the planar light source can have alight distribution characteristic. With the configuration, it ispossible to arrange a liquid crystal display device to be provided withsuch a planar light source as a BL (backlight) light source.

The present invention is not limited to the description of theembodiments above, but may be altered by a skilled person within thescope of the claims. An embodiment based on a proper combination oftechnical means disclosed in different embodiments is encompassed in thetechnical scope of the present invention.

A light emitting device of the present invention is a light emittingdevice including: a substrate; a plurality of light emitting elementsprovided on a primary surface of the substrate; at least one protectiveelement connected in parallel with the plurality of light emittingelement; a resin frame made of a resin having a low opticaltransmittance, the resin frame being provided annularly on the primarysurface of the substrate so as to surround a mounting area in which theplurality of light emitting elements are provided; afluorescent-material-containing resin layer made of a resin containingfluorescent materials, the fluorescent-material-containing resin layerbeing provided adjacent to an inner side of the resin frame so as tocover the plurality of light emitting elements; and at least one firstlight emitting element connection electrode and at least one secondlight emitting element connection electrode, which are provided on theprimary surface of the substrate so as to face each other along a firstdirection in the primary surface. The light emitting device of thepresent invention is configured such that (i) the plurality of lightemitting elements have such a circuit configuration that at least twoseries circuit sections, in each of which at least two of the pluralityof light emitting elements are connected in series, are connected inparallel between the at least one first light emitting elementconnection electrode and the at least one second light emitting elementconnection electrode, (ii) the at least two series circuit sections arealigned along a second direction orthogonal to the first direction inthe primary surface, between the at least one first light emittingelement connection electrode and the at least one second light emittingelement connection electrode, and (iii) the at least two of theplurality of light emitting elements in each of the at least two seriescircuit sections are aligned along the first direction, and (iv) the atleast one first light emitting element connection electrode and the atleast one second light emitting element connection electrode aredisposed below at least one of the resin frame and thefluorescent-material-containing resin layer.

In the light emitting device of the present invention, it is preferablethat (i) the plurality of light emitting elements be divided into aplurality of groups so that each of the plurality of groups includes acorresponding first light emitting element connection electrode and acorresponding second light emitting element connection electrode, (ii)the plurality of groups be aligned along the second direction, (iii)connection wiring lines be provided on the primary surface of thesubstrate so as to connect adjoining groups in series, and (iv) each ofthe at least one protective element be provided for each of theplurality of groups.

In the above configuration, the light emitting elements are disposed inseveral groups according to the number of light emitting elements andhow the light emitting elements are configured. This makes it possibleto minimize the mounting area in which the light emitting elements areto be provided. As a result, it is also possible to reduce an area inwhich to provide the first light emitting element connection electrodes,the second light emitting element connection electrodes, the resinframe, and the like. This makes it possible to downsize the lightemitting device. Further, the protective element is provided for each ofthe groups. As a result, it is possible to minimize a decrease in lightoutput when a series circuit section is disconnected.

In the light emitting device of the present invention, it is preferablethat the resin used for forming the resin frame be colored in white ormilky white. This makes it possible to set an optical transmittance ofthe resin used for forming the resin frame to be low, or to allow theresin used for forming the resin frame to have light reflectivity.

The light emitting device of the present invention is preferablyconfigured such that adjoining light emitting elements in each of the atleast two series circuit sections are wire-bonded to each other suchthat a cathode electrode of one of the adjoining light emitting elementsis directly connected, via a metal wire, to an anode electrode of theother one of the adjoining light emitting elements. This makes itpossible to reduce distances between light emitting elements, therebyincreasing a packaging density of the light emitting elements.

The light emitting device of the present invention is preferablyconfigured such that the at least one protective element is a thin-filmprinted resistor provided partially on the primary surface of thesubstrate, and the at least one protective element is provided on aperiphery of the mounting area and below at least one of the resin frameand the fluorescent-material-containing resin layer so as to beelectrically connected to the at least one first light emitting elementconnection electrode and the at least one second light emitting elementconnection electrode.

The light emitting device of the present invention is preferablyconfigured such that the at least one protective element is at least onethin-film printed resistor each provided partially on the primarysurface of the substrate, and each of the at least one protectiveelement is provided on a periphery of the mounting area and below atleast one of the resin frame and the fluorescent-material-containingresin layer so as to be electrically connected to a corresponding firstlight emitting element connection electrode and a corresponding secondlight emitting element connection electrode in a corresponding group.

With the above configuration, it is possible to easily form a resinframe, a fluorescent-material-containing resin layer, and the like on aprotective element(s). Accordingly, the flexibility of a layout of theprotective element(s) becomes high, thereby resulting in that theprotective element(s) can be disposed near the light emitting elementsor below the resin frame and the fluorescent-material-containing resinlayer. Further, when a largest possible part of the protectiveelement(s) is disposed below the resin frame so as to be covered withthe resin frame, it is possible to restrain light absorption by theprotective element(s) as much as possible.

In the light emitting device of the present invention, it is preferablethat the substrate be a ceramic substrate made of ceramic.

The light emitting device of the present invention is preferablyconfigured such that each of the plurality of light emitting elementsincludes a cathode electrode and an anode electrode, which are providedso as to face each other, and the plurality of light emitting elementsare aligned in a same orientation in which the cathode electrode and theanode electrode of said each of the plurality of light emitting elementsface each other along the first direction.

The light emitting device of the present invention is preferablyconfigured such that each of the plurality of light emitting elementsincludes a cathode electrode and an anode electrode, which are providedso as to face each other, and the plurality of light emitting elementsare aligned in a same orientation in which the cathode electrode and theanode electrode of said each of the plurality of light emitting elementsface each other along the second direction.

In the above configuration, all the light emitting elements are alignedin the same orientation. Accordingly, it is possible to die-bond thelight emitting elements without changing their orientation. This makesit possible to simplify a die-bond device/process. Further, in theconfiguration, along which direction the cathode electrode is oppositethe anode direction is selected in accordance with the shape of thelight emitting element. This accordingly makes it possible to preferablyreduce distances between the light emitting elements, thereby increasinga packaging density of the light emitting elements as much as possible.

The light emitting device of the present invention is preferably suchthat the thin-film printed resistor has a resistance value of 1 MΩ to 10GΩ.

The light emitting device of the present invention is preferably suchthat the resin frame has an annular shape when viewed in a plane manner.In the configuration, the fluorescent-material-containing resin layerhas a circular shape when viewed in a plane manner. Accordingly, lightemitted from the light emitting elements easily outputs in alldirection, uniformly. Further, with the above configuration, the lightemitting device can be easily applied to a general-purpose lightingapparatus, and such a general-purpose lighting apparatus to which thelight emitting device is applied can be easily designed.

INDUSTRIAL APPLICABILITY

The present invention can be preferably used in a field related to alight emitting device in which a plurality of LEDs are provided on asubstrate such that they are connected in a series-parallel connection.In addition to this, the present invention can be preferably used in afield related to a production method for producing a light emittingdevice. Furthermore, the present invention can be widely used in a fieldof electronics devices provided with a light emitting device.

REFERENCE SIGNS LIST

-   100, 200, 300, 400, 500, 600, 700, 800: Light Emitting Device-   101: Ceramic Substrate (Substrate)-   102: Electrode Wiring Patterns-   102 a/102 d/102 g/102 j: Connection Wiring Line-   102 b/102 e/102 h: Anode-side Electrode (First Light Emitting    Element Connection Electrode)-   102 c/102 f/102 i: Cathode-side Electrode (Second Light Emitting    Element Connection Electrode)-   103: Anode-side Electrode Land-   104: Cathode-side Electrode Land-   105, 105′: LED chip (Light Emitting Element)-   106: Wire (Metal Wire)-   107, 107 a to 107 e: Printed. Resistor (Protective Element)-   108: Dam Resin (Resin Frame)-   109: Fluorescent-material-containing Resin Layer-   900: LED Electric Bulb-   909: Light Emitting Device

1-9. (canceled)
 10. A light emitting device comprising: a substrate; aplurality of LED chips positioned around a center of a primary surfaceof the substrate; a resin frame made of resin that has lightreflectivity, formed on the primary surface of said substrate andprovided annularly so as to surround a mounting area in which saidplurality of LED chips are provided; an anode-side electrode land and acathode-side electrode land which are electrodes to be connected to anexternal voltage supply of said light emitting device, the anode-sideelectrode land and the cathode-side electrode land being providedoutside said resin frame and near peripheral end of the primary surfaceof the substrate; an electrode wiring pattern formed on the primarysurface of said substrate including (i) an anode pattern extending fromsaid anode-side electrode land to a portion under said resin frame and(ii) a cathode pattern extending from said cathode-side electrode landto the other portion under said resin frame, so as to electricallyconnect the plurality of LED chips to the anode-side electrode land andthe cathode-side electrode land; and a plurality of first wires forconnecting the LED chips among said plurality of LED chips to theelectrode wiring pattern, a portion of each of the plurality of firstwires that is contacted with the electrode wiring pattern being coveredby said resin frame.
 11. The light emitting device of claim 10, whereinsaid substrate has a rectangular outer shape in a top view.
 12. Thelight emitting device as set forth in claim 11, wherein the cathode-sideelectrode land is provided near a corner of the primary surface of thesubstrate, and the corner is diagonally opposite a corner where theanode-side electrode land is provided.
 13. The light emitting device asset forth in claim 11, wherein the anode-side electrode land and thecathode-side electrode land are disposed diagonally on the primarysurface of the substrate.
 14. The light emitting device as set forth inclaim 10, further comprising: a plurality of second wires forelectrically connecting the plurality of LED chips with each other, anda fluorescent-material-containing resin layer provided attaching to aninner side of the resin frame and covering the plurality of LED chipsand the second wires.
 15. The light emitting device as set forth inclaim 14, wherein the fluorescent-material-containing resin layer isprovided along a shape of the resin frame so as to have a circular shapein the top view.
 16. The light emitting device of claim 10, wherein eachof said anode-side electrode land and said cathode-side electrode landhas a width larger than that of said electrode wiring pattern.
 17. Thelight emitting device of claim 10, wherein said substrate comprisesceramic, and said plurality of LED chips are attached to the primarysurface of said substrate via a resin adhesive agent comprisingsilicone.
 18. The light emitting device of claim 10, further comprisingprotection films provided on the anode and cathode patterns.
 19. Thelight emitting device of claim 10, wherein said anode pattern furtherextends to the mounting area.
 20. The light emitting device of claim 10,wherein said cathode pattern further extends to the mounting area.
 21. Alight emitting device comprising: a substrate; a plurality of LED chipspositioned around a center of a primary surface of the substrate; aresin frame made of resin that has light reflectivity, formed on theprimary surface of said substrate and provided annularly so as tosurround a mounting area in which said plurality of LED chips areprovided; an anode-side electrode land and a cathode-side electrode landwhich are electrodes to be connected to an external voltage supply ofsaid light emitting device, the anode-side electrode land and thecathode-side electrode land being provided outside said resin frame andnear peripheral end of the primary surface of the substrate; anelectrode wiring pattern formed on the primary surface of said substrateincluding (i) a first anode pattern provided on a portion under saidresin frame and (ii) a first cathode pattern provided on the otherportion under said resin frame, the first anode pattern and the firstcathode pattern electrically connecting the plurality of LED chips tothe anode-side electrode land and the cathode-side electrode land; aplurality of first wires for connecting first chips among the pluralityof LED chips to the first anode pattern, a portion of each of theplurality of first wires that is contacted with the first anode patternbeing covered by the resin frame; and a plurality of second wires forconnecting second chips among the plurality of LED chips to the firstcathode pattern, a portion of each of the plurality of second wires thatis contacted with the first cathode pattern being covered by the resinframe.
 22. The light emitting device as set forth in claim 21, whereinsaid substrate has a rectangular outer shape in a top view.
 23. Thelight emitting device as set forth in claim 22, wherein the cathode-sideelectrode land is provided near a corner of the primary surface of thesubstrate, and the corner is diagonally opposite a corner where theanode-side electrode land is provided.
 24. The light emitting device asset forth in claim 22, wherein the anode-side electrode land and thecathode-side electrode land are disposed diagonally on the primarysurface of the substrate.
 25. The light emitting device as set forth inclaim 21, further comprising: a plurality of third wires forelectrically connecting the plurality of LED chips with each other, anda fluorescent-material-containing resin layer provided attaching to aninner side of the resin frame and covering the plurality of LED chipsand the third wires.
 26. The light emitting device as set forth in claim25, wherein the fluorescent-material-containing resin layer is providedalong a shape of the resin frame so as to have a circular shape in thetop view.
 27. The light emitting device of claim 21, wherein saidanode-side electrode land has a width larger than that of the firstanode pattern, and said cathode-side electrode land has a width largerthan that of the first cathode pattern.
 28. The light emitting device ofclaim 21, wherein said substrate comprises ceramic, and said pluralityof LED chips are attached to the primary surface of said substrate via aresin adhesive agent comprising silicone.
 29. The light emitting deviceof claim 21, wherein the electrode wiring pattern further includes (iii)a second anode pattern connected between said anode-side electrode landand the first anode pattern and (iv) a second cathode pattern connectedbetween said cathode-side electrode land and the first cathode pattern.30. The light emitting device of claim 29, further comprising protectionfilms provided on the second anode and cathode patterns.